Assessment and Classification of Overweight/Obesity

Assessment of Other Risk Factors

Strategies for Prevention of Obesity

Management of Overweight and Obesity

• To examine the pathophysiology and epidemiology of overweight in children and adolescents
• To present updated information on the adverse outcomes associated with childhood overweight and discuss approaches for the prevention and treatment of overweight in young individuals

• To provide best practice guidelines focused on the primary prevention of obesity in children from birth to age 18 years
• To provide direction for nurses who work with children and families across diverse practice settings and at population, family, and/or individual levels

Note: Treatment of obesity is not within the scope of this guideline.

• To assist health care professionals who have a role in managing overweight or obese patients
• To provide current evidence-based clinical practice recommendations on various aspects of obesity management found across various medical disciplines
• To provide a framework to assist doctors in the management of overweight and obesity without restricting the physician's individual judgment
• To provide a review of the various medical, surgical, and ancillary intervention modalities in the management of obesity
• To aid primary care physicians in basic management of obesity and subsequent referrals to specialists for more resistant cases

• To summarize the USPSTF recommendations on screening for overweight in children and adolescents and the supporting scientific evidence

• United States
• Infants, children, and adolescents in the general population (prevention)
• Overweight or obese children and adolescents with or without comorbidities (prevention and treatment)

• Canada
• Children from birth to age 18 years

• Singapore
• Children and adolescents who are obese or overweight, or who are at risk of obesity

Note: The guideline also targets adults who are obese or overweight or who are at risk for obesity. This target group is addressed in a companion synthesis, Assessment and Treatment of Obesity and Overweight in Adults.

• United States
• Asymptomatic children and adolescents (aged 6 to 19 years) seen in primary care

Health Care Provider
Physicians

Advanced Practice Nurses
Nurses

Advanced Practice Nurses
Allied Health Personnel
Dietitians
Nurses
Physician Assistants
Psychologists/Non-physician Behavioral Health Clinicians
Public Health Departments
Respiratory Care Practitioners

Advanced Practice Nurses
Allied Health Personnel
Dietitians
Health Care Providers
Health Plans
Managed Care Organizations
Nurses
Physician Assistants
Physicians

For children in the United States, overweight is defined using CDC age- and sex-specific nomograms for BMI. A BMI percentile >5th and <85th is considered normal weight for height; the 85th to the 95th percentile is considered at risk for overweight; and >95th percentile is defined as overweight. By late adolescence, these percentiles approach those used for adult definitions; the 95th percentile is approximately 30 kg/m². A recent report from the Institute of Medicine has specifically used the term "obesity" to characterize BMI >95th percentile in children and adolescents. The term obesity was used in this report in part to more effectively convey the seriousness, urgency, and medical nature of this problem. Thus, the terms overweight and obesity are often used interchangeably in pediatric patients.

• Children <85th percentile with no other health risk factors should be screened (weight, height, and BMI percentile calculated and plotted) every year. Identification of risk for overweight before adolescence is encouraged so that health habits can be improved at a stage of increased parental influence and control.
• Primary care providers should assess diet and activity habits at annual well-child visits; this should be routinely integrated into the overall care plan.

Nurses assess physical growth and development of children and adolescents which includes:

• Discussing and documenting basic dietary patterns (Level IV)
• Discussing and documenting physical activity patterns including sedentary activity (e.g., television and computer time) (Level IV)
• Identifying individual and family risk factors for childhood obesity
• Accurately measuring and recording height and weight (Level IV)
• Calculating BMI for children two years of age and older (Level IV)
• Plotting BMI for age on appropriate CDC pediatric growth charts (Level IV)
• Monitoring changes in BMI, dietary and physical activity patterns over time and noting important variations (Level IV)

Definitions

• Overweight: Classification of overweight children is currently a BMI (age and gender specific) >85th percentile and <95th percentile. Research studies often use recently recommended international cut-offs corresponding to a BMI of 25-29.9 used in adults.
• Obesity: A condition of excess body fat. There is no direct measure of body fat in childhood that is readily applicable in the clinical setting. The current recommendation is for use of BMI for age and gender above 95th percentile using CDC growth curves to define those at increased health risk because of overweight. A new international cut-off for BMI which corresponds to the adult levels of 25 and 30 for overweight and obesity respectively are recommended for population studies.

• Historically, weight-for-height charts have been used to classify weight status in children. BMI-for-age and gender charts are recommended for use in children. (Grade B, Level III)
• A full clinical evaluation and possible treatment should be considered in children with a BMI >95th percentile or a BMI >85th percentile and complications of obesity. Alternatively, BMIs-for-age and gender equivalent to adult World Health Organization (WHO) BMI cut-offs for obese and overweight (at >30.0 or >25.0 kg/m²) respectively can be used as thresholds, although BMI cut-offs for action among Asians of 27.5 and 23.0 kg/m² respectively may eventually be used. (Grade C, Level IV)

• It is important to measure and monitor growth over time in all children as an indicator of health and development.
• BMI (calculated as weight in kilograms divided by height in meters squared) percentile for age and sex is the preferred measure for detecting overweight in children and adolescents because of its feasibility, reliability, and tracking with adult obesity measures. BMI values are CDC population-based references for comparison of growth distribution to those of a larger population. Being at risk for overweight is defined as a BMI between the 85th and 94th percentile for age and sex, and overweight as a BMI at or above the 95th percentile for age and sex. Disadvantages of using BMI include the inability to distinguish increased fat mass from increased fat-free mass, and reference populations derived largely from non-Hispanic whites, potentially limiting its applicability to non-white populations.
• Indirect measures of body fat, such as skinfold thickness, bio-electrical impedance analysis, and waist-hip circumference, have potential for clinical practice, treatment, research, and longitudinal tracking, although there are limitations in measurement validity, reliability, and comparability between measures.

Identification of risk for overweight before adolescence is encouraged so that health habits can be improved at a stage of increased parental influence and control

• Identify individual and family risk factors for childhood obesity (Level IV)

The nurse's assessment should include questions and observations related to individual or familial obesity risk factors. Studies have shown that children who have a genetic propensity for weight gain are more likely to become obese if they grow up in an environment that promotes overeating and inactivity.

Numerous studies confirm that when parents are obese, the risk of persistent obesity in their children increases three-fold. Monogenic (single gene) causes of obesity are being described with increasing frequency; this familial link to obesity, however, continues to represent only a minority of children with obesity. From a prevention perspective, it is more important to note that lifestyle patterns relating to nutrition and physical activity develop within the context of the family. Dietary energy and fat intake and physical activity profiles in children closely reflect those of their parents. Physical activity in pre-school children can be related to parental BMI. Reduced physical activity and increased sedentary behaviours in childhood are associated with higher levels of overweight and obesity.

Rates of overweight and obesity also vary by family income. The importance of a number of additional risk factors including gestational diabetes and maternal smoking during pregnancy, reduced fetal growth, and bottle-feeding during infancy on the development of overweight in childhood remains to be fully elucidated.

Overweight in a child under 3 years of age does not predict future obesity, unless at least one parent is also obese. After 3 years, the likelihood that obesity persists increases with advancing age of the child, and is higher in children with severe obesity in all age groups. The presence of obesity in at least one parent increases the risk of persistence in children at every age.

In clinical evaluation of patients, practitioners should consider and exclude predisposing factors for, and secondary causes of, obesity. (Good Practice Point)

No recommendations offered.

Population-specific Interventions

For a public health approach, the most desirable prevention goal is to prevent children with a normal, desirable BMI (<85th percentile) from becoming at risk of overweight or overweight. Other levels of prevention also apply to a lesser degree: primary prevention, aimed at preventing at-risk-of-overweight children from becoming overweight (BMI >95th percentile), and secondary prevention, aimed at the treatment of overweight children to reduce comorbidities, reduce the severity of the problem, and normalize weight, if possible. Success is most likely to occur if appropriate prevention strategies and interventions are initiated throughout the life course, beginning in infancy. Strategies tailored to children in ethnic minority populations with a disproportionate risk of becoming obese are also needed.

Infants

Promoting breast-feeding is a promising prevention strategy given its potential protective effect on later obesity and overall benefits for nutrition. Such efforts require more attention to the incentives and barriers that affect rates of breast-feeding by different subgroups within the population, including the social and environmental variables that support or discourage women's decisions to breast-feed.

Toddlers

Strategies to achieve an optimal rate of pounds gained per inch might help families and children acquire the critical life skills to enable them to better balance energy intake (diet) with energy expenditure (physical activity). Goals are to work toward establishing healthy environments at home, at school and in the community that encourage families and children to practice and maintain the life skills that are conducive to maintaining a healthy weight.

The important role of parenting skills and teacher training in helping young children learn and practice healthful behaviors has increasingly been recognized. Behavior targets include increasing consumption of fruits and vegetables ("5-a-day"), increasing consumption of fiber-containing grain products, switching from full-fat to 1% or fat-free dairy products after 2 years of age, preparing and eating family meals at home, increasing daily physical activity (e.g., active play 1 h/d), and limiting sedentary time (e.g., watching television <2 h/d).

School-Age Children and Adolescents

Most efforts to prevent obesity among school-age children and adolescents have been implemented in school settings. There is ample evidence that theory-based interventions that include classroom curricula, physical education curricula, changes in school meals, vending machines, and cafeterias, and after-school programs, can increase physical activity and improve dietary patterns in children and adolescents. Additional attention paid to applying theoretical models to develop interventions that are more relevant and motivating to children has produced a growing body of theory-based interventions in schools that have successfully reduced weight gain and obesity.

Exposure to various media may be important in considering population-based prevention efforts. For example, a substantial proportion of the advertising on children's television promotes food, and there is a direct relationship between television viewing and obesity. Furthermore, reducing television viewing has reduced weight gain and the prevalence of obesity in experimental trials.

Children in Ethnic Minority Populations

The challenge of obesity prevention includes the need to develop tailored strategies that are well matched to the social and cultural contexts of children in ethnic minority populations with a high risk of obesity. Eating, activity, and perceptions of weight and health are strongly influenced by cultural norms and culturally influenced attitudes and values. The relevant variables can be considered from programmatic, child, familial, and environmental perspectives that are then each specified along multiple related dimensions such as ethnic identification and related cultural attitudes, beliefs, and values; family and household characteristics; and socioeconomic status variables. Theoretical guidance to inform systematic approaches to developing culturally specific prevention strategies is available but not yet fully used or developed in relation to the specifics of obesity prevention.

Setting-specific Approaches

Setting-specific approaches target institutions that provide access to groups of children. Potential childhood obesity prevention settings include schools, Head Start programs, and other centers where preschoolers participate in groups; homes, where preschool children are cared for by parents and other caregivers; healthcare settings, where growth and weight status are routinely monitored; industries that develop television programs and other media, print books, and toys for preschoolers; and community and government programs and policies that affect families with young children. Typical interventions in physical settings are based on individual behavioral theories and designed to enhance motivation and teach behavior-change skills in large groups. In group settings, hands-on experiences with food or activity are often provided on site.

Interventions in health care that teach providers effective counseling or deliver additional services can be effective, but there are significant barriers to implementation in such settings.

Community-wide approaches include coordinated interventions in multiple settings and may include mass media components.

Environmental and policy approaches are based on the concept that education and motivational interventions will be more effective in social and physical environments where healthful choices are the easier choices. Relevant environments include physical (what is available and promoted; e.g., food choices in homes, fast food advertisements on television, opportunities for or barriers to physical activity); economic (financial factors; e.g., the price of soda versus water, subsidies to sugar farmers); policy (rules; e.g., school food service standards, regulations on marketing that targets young children); and sociocultural (attitudes, perceptions, beliefs, and values such as fast food, everyday food, personal responsibility, and the ethos of governments).

1. Nurses promote healthy eating and physical activity throughout the lifecycle beginning at an early age. (Level IV)
2. Nurses advocate for healthy public policies that include:
   • Monitoring and surveillance data at the population level regarding (Level IV):
     • Nutrition
     • Physical activity
     • Measures of adiposity including obesity and overweight status
   • Healthy community design. (Level IV)
   • Health promoting school policies. (Level IIb)
   • Legislation to limit advertising directed towards children. (Level IIb)
   • Community-wide campaigns. (Level Ia)
3. Nurses promote healthy eating and physical activity at population, community, family, and individual levels by planning, implementing, and evaluating interventions that are:
   • Tailored to the strengths and needs of the client and are (Level IV):
     • Developmentally appropriate
     • Culturally and linguistically relevant
     • Gender-specific
   • Affordable and accessible (Level IV)
   • Focused on behaviour change (Level IIb)
4. Nurses maximize the effectiveness of their healthy lifestyle interventions through interactions that are of sufficient intensity and duration to effect behaviour change. (Level Ia)
5. Nurses support exclusive breastfeeding for infants until six months of age. (Level III)
6. Nurses promote healthy eating using Canada's Food Guide to Healthy Eating and focus on:
   • Using age-appropriate portion sizes
   • Emphasizing fruits and vegetables
   • Limiting sugar containing beverages (e.g., soft drinks and fruit juices)
   • Limiting consumption of energy-dense snack foods high in sugar and fat (e.g., potato chips, french fries, candy)
   • Breakfast consumption (Level IV)
7. Nurses promote healthy eating patterns using interventions with one or more of the following components:
   • Small group activities
   • Goal setting
   • Social support
   • Interactive food-related activities (e.g., cooking, taste-testing)
   • Family participation (Level Ia)
8. Nurses promote increased physical activity based on Canada's Physical Activity Guides for Children and Youth using interventions with one or more of the following components
   • Behaviour modification. (Level Ib)
   • Leisure activity of low intensity that is gradually increased to recommended levels. (Level IV)
   • Sustained, repeated interventions. (Level IV)
9. Nurses promote a decrease in sedentary activities with emphasis on reducing the amount of time clients spend watching TV, playing video games, and engaging in recreational computer use. (Level Ib)
10. Nurses work with school communities to implement school-based strategies for the prevention of obesity using a multi-component approach including:
    • Integrating healthy lifestyle messages into curricula
    • Advocating for and supporting the implementation of quality daily physical education taught by specialist physical education teachers
    • Advocating for and supporting the implementation of quality daily physical activity (including vigorous physical activity)
    • Using youth driven approaches with an information and advocacy component
    • Offering healthy choices in cafeterias and vending machines
    • Increasing physical activity opportunities at recess and during lunch breaks
    • Forming community partnerships and coalitions (Level Ia)
11. Nurses support a family-centred approach to promote healthy eating and physical activity. (Level III)
12. Nurses assist clients to access community resources and opportunities to engage in healthy eating and physical activity through:
    • Direct referral of clients to community resources
    • Dissemination of information about available community resources
    • Promotion of low and no cost physical activity options (e.g., hiking, walking, active commuting, and subsidized programs) (Level IIa)
13. Nurses are aware of, refer to, and collaborate with appropriate allied health providers based on findings from nursing assessment. (Level IV)

No recommendations offered.

• The USPSTF concludes that the evidence is insufficient to recommend for or against routine screening for overweight in children and adolescents as a means to prevent adverse health outcomes. I Recommendation

The USPSTF found fair evidence that body mass index (BMI) is a reasonable measure for identifying children and adolescents who are overweight or are at risk for becoming overweight. There is fair evidence that overweight adolescents and children aged 8 years and older are at increased risk for becoming obese adults. The USPSTF found insufficient evidence for the effectiveness of behavioral counseling or other preventive interventions with overweight children and adolescents that can be conducted in primary care settings or to which primary care clinicians can make referrals. There is insufficient evidence to ascertain the magnitude of the potential harms of screening or prevention and treatment interventions. The USPSTF was, therefore, unable to determine the balance between potential benefits and harms for the routine screening of children and adolescents for overweight.

Clinical Considerations

• It is important to measure and monitor growth over time in all children as an indicator of health and development. The conclusion that there is insufficient evidence to recommend for or against screening for overweight in children and adolescents reflects the paucity of good-quality evidence on the effectiveness of interventions for this problem in the clinical setting. There is little evidence for effective, family-based or individual approaches for the treatment of overweight in children and adolescents in primary care settings. The CDC's Guide to Community Preventive Services has identified effective population-based interventions that have been shown to increase physical activity, which may help reduce childhood overweight.

The principal strategies for the treatment of overweight in children are similar to those for adults (dietary modification and increased physical activity), with treatment goals based on age, severity of obesity, and the results of risk factor assessment.

Guiding Principles

Five guiding principles are important for the treatment of overweight. These guiding principles can be summarized as follows:

1. Establish individual treatment goals and approaches based on the child's age, degree of overweight, and presence of comorbidities.
2. Involve the family or major caregivers in the treatment.
3. Provide assessment and monitoring frequently.
4. Consider behavioral, psychological, and social correlates of weight gain in the treatment plan.
5. Provide recommendations for dietary changes and increases in physical activity that can be implemented within the family environment and that foster optimal health, growth, and development.

Treatment of overweight should rarely be instituted before 2 years of age because of the rapid growth and development that occurs during these early years and lower correlation with overweight in later years.

Family involvement is critical in the treatment of childhood overweight. If treatment is initiated when a family is not ready to support the program, then success is unlikely. The treatment planned should also take into consideration long-term management with the continued assessment of the child for adequate growth and development because overweight is a long-term problem

Dietary Management

• Age-specific dietary modification is the cornerstone of treatment. The major goals in dietary management are to provide appropriate calorie intake, provide optimum nutrition for the maintenance of health and normal growth, and to help the child develop and sustain healthful eating habits.
• Estimated energy requirements vary throughout childhood and reflect large increments with a range of 570 to 3,152 kilocalories/day for boys and 520 to 2,368 kcal for girls from age 3 months to 16 years. In addition, caloric needs may vary widely even for children of the same age because of normal differences in size. Thus, individualizing the calorie-intake recommendation and monitoring weight change are essential. Healthcare professionals must help parents or caregivers recognize and prevent overeating.
• Because it is difficult for parents to judge calorie intake and energy expenditure on a regular basis, it is necessary to help parents guide the diet and physical activity patterns of their children. Counseling and recommendations must be made within the context of the family's culture, living environment, and socioeconomic status. Involving children in meal planning, shopping, gardening, and preparation of food has been promoted, along with including all caregivers (including grandparents) in helping the child to adhere to recommended consumption patterns and healthier food choices.

Physical Activity

• Regular physical activity is critical for the prevention of abnormal weight gain and weight maintenance. The current recommendation for the amount of physical activity is 30 to 60 minutes of regular exercise daily. "Working up a sweat" during the activity suggests adequate effort expended. These recommendations apply to children of normal weight as well as to children who are overweight.
• Recommended activities must be enjoyable and congruent with the child's and family's lifestyle and be rewarding independent of the health benefit.
• A complementary approach is to restrict sedentary free-time activities to <2 hours/day.

Pharmacological Treatment

• Data supporting the use of pharmacological therapy for pediatric overweight are limited and inconclusive.
• Sibutramine has been studied in a randomized controlled trial of severe obesity. It has been shown to be efficacious as compared with behavior therapy alone, but it may be associated with side effects including increases in heart rate and blood pressure.
• Orlistat is approved for use in adolescence. The efficacy of orlistat has not been tested extensively in young patients. Orlistat is associated with gastrointestinal side effects and requires fat-soluble vitamin supplementation and monitoring.
• For rare genetic and metabolic disorders, pharmacological treatment may be useful. For example, recombinant leptin is useful in hereditary leptin deficiency. Octreotide may be useful in hypothalamic obesity. Metformin, used to treat type 2 diabetes mellitus, has been used in insulin-resistant children and adolescents who are overweight, but long-term efficacy and safety are unknown.

Surgical Treatment

• Surgical approaches to treat severe adolescent obesity are being undertaken by several centers. Indications used include a BMI >40 kilogram/m² and severe associated comorbidities, such as obstructive sleep apnea, type 2 diabetes mellitus, and pseudotumor cerebri.
• More severe elevation of BMI (>50 kilogram/m²) may be an indication for surgical treatment in the presence of less severe comorbidities such as hypertension and dyslipidemia, particularly if the degree of overweight hinders performing the activities of daily living.
• An experienced team approach including comprehensive medical and psychological evaluation is critical both for selection of appropriate candidates and for postoperative care that is sophisticated and often intense.
• Weight loss goals and reduction of morbidity are often achieved with gastric bypass surgery. The rates of short-term mortality appear to be low, but significant complications can occur. Intermediate and long-term outcomes, including information on malabsorption of critical nutrients, are unknown.
• Overall, surgical therapy should be reserved for full-grown adolescents with the severest obesity-related morbidity, offered only by experienced multidisciplinary teams, and presented to families with appropriate informed consent procedures.

No recommendations offered.

Dietary Changes

• In children, less restrictive diets should be used, rather than diets consisting of drastically altered portions of various nutrients, very low calorie diets, or protein sparing modified fast regimens. (Grade B, Level III)

Physical Activity

• Appropriately increased physical activity is recommended. Younger children generally need age-appropriate creative activities with generous periods of free play. Weight bearing activities are recommended for overweight children, non-weight bearing activities for obese children, and preferably supervised activities for severely obese children. In the older obese pre-adolescent and adolescent, decreased time on sedentary pursuits and increased activity such as a moderate intensity, progressive exercise program with increasing levels of obesity are recommended. (Grade B, Level III)

Behaviour Modification

• Behaviour-treatment programs have shown consistent success in weight loss. (Grade B, Level IIa)

Family Involvement

• Interventions for obesity in children should be directed at both the parents and the child, rather than the child alone. (Grade B, Level III)

Pharmacotherapy

• There is no data on the long term efficacy and safety of medication in childhood and adolescent obesity. (Grade C, Level IV)

Bariatric Surgery

• Bariatric surgery cannot be recommended for most adolescents, but only for those at the highest risk of mortality from obesity, and with both patient and parental understanding of the consequences of surgery. (Grade B, Level III)

Insufficient evidence is available on the effectiveness of interventions for overweight children and adolescents that can be conducted in primary care settings or to which primary care clinicians can make referrals.

No specific recommendations are given concerning management of overweight and obesity.

The short- and long-term association of obesity with morbid outcomes raises the level of importance for understanding overweight as a major public health concern for children and adolescents. Prevention and treatment of overweight and obesity in children and adolescents may help prevent these adverse outcomes.

Interventions to improve nutrition and physical activity in children may provide children with immediate benefits such as:

• Improvements in adult health
• Modify chronic disease risks in childhood, thereby lowering rates and risks in adults
• Modify children's health behaviours and thereby lead to improved and sustained behaviours in adulthood that could further reduce risks for a variety of chronic diseases

Successful control of childhood obesity reduces likelihood of obesity in later life and prevalence of obesity-related disorders.

Appropriate screening for overweight in children and adolescents

• Sibutramine has been studied in a randomized controlled trial of severe obesity. It has been shown to be efficacious as compared with behavior therapy alone, but it may be associated with side effects including increases in heart rate and blood pressure.
• Orlistat is associated with gastrointestinal side effects and requires fat-soluble vitamin supplementation and monitoring.
• The rates of short-term mortality appear to be low, but significant complications can occur with surgical treatment of obesity. Intermediate and long-term outcomes, including information on malabsorption of critical nutrients, are unknown.

None stated

Potential harms associated with the implementation of the guideline are detailed in the NGC summary. No harms are specifically noted regarding the prevention and management of obesity in children and adolescents. Refer to the NGC summary for details.

There is insufficient evidence on the harms of screening. Potential harms of screening include labeling, induced self-managed dieting with negative sequelae, poor self-concept, poor health habits, disordered eating, or negative impact from parental concerns. These theoretical harms are inferred from studies of limited design. There also is insufficient evidence on the harms of interventions. Among 4 recent behavioral intervention trials, adverse effects were reported in 1 trial. Among those who completed an intervention (37/44) in a good-quality RCT in a primary care setting, no problematic eating was detected in the adolescent participants after treatment. During the placebo-controlled phase of the sibutramine trial, 19 of 43 patients (44%) in the group receiving sibutramine had their dosage reduced or discontinued because of elevated blood pressure, pulse rate, or both. No other adverse events were reported.

Levels of Evidence

Ia - Evidence obtained from meta-analysis or systematic review of randomized controlled trials

Ib - Evidence obtained from at least one well-designed randomized controlled trial

IIa - Evidence obtained from at least one well-designed trial without randomization

IIb - Evidence obtained from at least one other type of well-designed quasi-experimental study, without randomization

III - Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies

IV - Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities

Grades of Recommendations

Grade A (evidence levels Ia, Ib): Requires at least one randomised controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation

Grade B (evidence levels IIa, IIb, III): Requires availability of well conducted clinical studies but no randomised clinical trials on the topic of recommendation

Grade C (evidence level IV): Requires evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. Indicates absence of directly applicable clinical studies of good quality

GPP (good practice points): Recommended best practice based on the clinical experience of the guideline development group

Levels of Evidence

Level Ia: Evidence obtained from meta-analysis of randomised controlled trials

Level Ib: Evidence obtained from at least one randomised controlled trial

Level IIa: Evidence obtained from at least one well-designed controlled study without randomisation

Level IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study

Level III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies

Level IV: Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities

Strength of Recommendations

The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):

A

The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.

B

The USPSTF recommends that clinicians provide [the service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.

C

The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.

D

The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.

I

The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.

Strength of Evidence

The U.S. Preventive Services Task Force (USPSTF) grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):

Good

Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.

Fair

Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.

Poor

Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.